by Triana Rathads

Created on: April 11, 2009

Vaccines are non-toxic antigenic products which are either injected, ingested or inhaled, which induce an immune response specific against a particular pathogen, it works by promoting an immune response without the disease of the pathogen. A good vaccine should be able to create a immunological memory, which is life long, and with no side effects, it also helps if it is cheap to make, easy to administer, and stable under different conditions, such as high temperature. It is also important to know the exact composition, and the

Vaccines are important because they prevent disease, and they are usually cost effective and efficient. There are four types of vaccines, killed attenuated, live attenuated, component, conjugate, and DNA vaccines.

Inactivated vaccines are killed pathogens, the antigens preserved within the vaccine can be a number of types, such as capsules, membrane proteins, toxins, or cell wall lipopolysaccharide. An example would be formaldehyde inactivated bacteria, preserved in phenol and then combined with an adjuvant (a molecule which induces an immune response), this type of vaccine is the most widely used, because it is the easiest and cheapest type of vaccine. It is administered via an intramuscular injection, however several injections may be required further because the vaccine creates a poor level of mucosal and cellular immunity, although an advantage of this type of vaccine is passive immunity to the offspring of those vaccinated.

Live attenuated (non-pathogenic) vaccines can be administered via an injection, intranasally, or orally. So what does attenuated mean, and is it safe, this type of vaccine is developed through the creation of a modified organism which is as similar to the original pathogen as possible, but without the manifestation of disease. A positive factor for this type of vaccine is that because the organism is still alive, it is able to reproduce, providing a sustained dose of the antigens, which creates the desired immune response, such as memory immunity. There are significant advantages to this vaccine type, such as a self limiting infection can mimic a pathogens natural infection, which would create a more natural and stronger immune response, especially mucosal immune responses with oral administration. The possible disadvantages of such a vaccine, are that mutations could occur within the vaccine organism which could revert it back to its pathogenic form, it may not be suitable for immunocompromised individuals, and

• 1
• 2
• Next Page >>